// (double edgeControlPosition, double edgeControlSize,
// double headLength, double headWidth, double shaftControlPosition,
// double shaftControlSize, float shaftPosition, double shaftThickness)
ArrowStyle arrowStyle = new ArrowStyle(0.5, 0.5, thickness*5,
thickness*5, 0.5, 0.5, 0, thickness);
GeomPoint fullVect = end.subtract(start);
double halfWidth = (arrowStyle.headWidth != -1) ? arrowStyle.headWidth/2 : arrowStyle.headLength/2;